Transformer.



A. S. HUBBARD. TRANSPORMER. APPLIOATION FILED SEPT. 24,1909.

kmim@ MfS/M Patented Oct. 6, 1914.

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BATTERY COMPANY, L CORPORATION OF NEW YORK.i

TRANSFORTJIER.

To alt who/m, it may concern Be it known that I, ALBERT S. HUBBARD, acitizen of the United States, and a resident of Belleville, county vofEssex, and State of New Jersey, have invented certain new and usefulImprovements in Transformer-s, of which the following is aspecification.

My invention relates to improvements in transformers, and especially totransformers which are particularly adapted for use as pieces ofregulating apparatus in alternating current systems of distribution.

One object of my invention is to provide ai arrangement in which anumber of turns in circuit of one'of the coils of the transformer may begradually varied as distinguished from step by step variations, and atthe saine time preventing any material loss of energy due to the self ormutual induction of a short-circuited turn.

A further object of my invention is to provide an arrangement wherebythe resistance variations due to the contact with such a short-circuitedturn, may be properly compensated for.

Further objects, features and advantages will more clearly appear fromthe detailed description given below, taken in connection with theaccompanying drawing which forms a part of this specification, and whichshows diagrammatically an arrangement embodying one foiin ofmy-invention.

In the drawing, 1 represents a laminated iron core forming a closedcircuit for the iiux of a transformer provided on one side with theprimary winding 2. r1`he secondary winding consists of a plurality ofturns 3 in the Vform of a helix, which are/preferably turned up on ascrew-cutting lathe. The helix 3 has secured thereto a short circuitedslip ring 4 and a gear 5. Since the path of the transformerflux iswholly in iron all or most of the iiux passes through the ring 4. Thatis, the flux passing through the ring 4 is substantially the saine inamount as that passing through the turns of helix 3. The parts 3, 4 and5 are all secured together and arranged to he rotated about the core 1by means of a motor 6 and gear 7.

The helix 3 is electrically connected with the ring or turn/4 'at 8 andthe ring or turn 4 consists of a short-circuited turn' of highresistance so that any current induced therein will be` small on accountof the high re- Specification of Letters Patent.

Application led Sheptember 24, 1509.

Patented Oct. 6, 1914. serial No. 513,365.

sistance of the circuit. For this purpose the ring 4 may be made ofcarbon, resistance metal or other`well known relatively high resistancematerial or structure. r1`he high resistance of the ring 4 may beproduced by making the ring of -high .resistance metal or in any othersuitable Way. In other words, the resistance of the ring` or turn 4 isrelatively large as compared with the turns of the helix 3. A brush 9 isarranged to contact with the surface of the slip ring 4 so as to formone terminal of a regulating circuit of which the conductor 10 forms apart. 11 .represents a brush forming the other terminal of theregulating circuit connected to the conductor 12, and the brush 11 isarranged to travel along the turns of the helix 3 as the same revolvesto cut more or less of said. turns in circuit. The action of the brush11 is not, however, step by step, but the brush moves gradually alongeach turn so that extremely fine adjustments may be had. i

Driven by the gear 7 is a gear 13 secured to shaft 14 which iii turndrives a disk 15 having around its periphery a slip ring 16 in allrespects similar to the slip ring 4. Also upon the shaft 14 there is asmall slip ring 17 of small resistance and a brush 18 is arranged tocontact therewith to connect the same with one terminal of theregulating circuit by means of conductor 19. Bearing upon the peripheryof the slip ring or short-circuited turn 16 is another brush 20 which iselectrically connected with the con-- ductor 10.

If the ring 4 were made of low resistance metal then the large number oflines of force passing through the core 1, would induce a very heavycurrent in the slip ring 4, since it is short-circuited. This heavycurrent would thereforel cause a considerable loss of energy, and wouldvery disadvantageously affect them operation of the transformer asapiece of regulating apparatus. But by forming the slip ring 4 of suchmaterial that it has a very high resistance only ay small current will'flow therein dueto this induction. But since the ring 4 is of highresistance, it will be lapparent that as the helix 3 revolves and thepoint 8 moves farther away from the brush 9, that a considerable amountof resistance is inserted in series with the helix 3. In order tocompensate for this variation in resistance, the

conductor 21, the conductor 21 being so ar- .5 ranged that it isconnected to the slip ring 16 opposite the brush 2O when Vthe-point 8 isdirectly under the brush 9. 'Thus as the point 8 moves farther away fromthe brush 9, the point 22 comes nearer the brush 20 so 10 that theresistance of that portion of the ring 16 in the circuit is decreasedJust as much as the resistance of that portion of the ring 4 'includedin circuit is increased. I t

will be apparent also that as the point 8 1s brought nearer the brush 9,the point 22 will be carried farther away from the brush -20 so thatcorrect compensation is always maintained.

From the above it will be apparent that 1 20 have provided anarrangement in which the transformer action may be adjusted evento thefinest degree, and yet the deleterious 1nduction due to theshort-circuited vturn is cut down so that it is immaterial.V Theaddition of the slip ring 16 provides means for compensating for anychanges 1n the reslstance of the circuit due to the high resistance ofthe slip ring 4.

Although I have described my improvements in great detail, neverthelessI do not desire to be limited thereto except as specified hereinaIter inthe claims, since many modiications within the spirit and scope of theinvention will be apparent to those skilled in the art, but

Having fully and clearly described my invention, what I claim as new anddesire to secure by Letters Patent, is:

1. A transformer having a core Jforming a closed magnetic circuitcarrying primary and secondary windings, one of said windings having ashort'eircuit turn forming one terminal of the winding, said winding andturn being rotatable with respect to the core but fixed longitudinallywith respect to the core, a brush adapted to move longitudinally withrespect to the core to contact with the various turns of the winding andform the other terminal thereof and means for compensating forvariations in the resistance of the circuit due to the movement ofthe'brush with respect to the turn.

2. A transformer having a closed magnetic circuit and having ashort-circuited turn of highv resistance for forming one terminal of thetransformer winding, a brush engaging said terminal and movablerelatively about the turn, and means for compensating for variations inthe resistance of the circuit, due to the movement of f the brush withrespect to the turn.

3. A transformer having a coil, a slip ring of high resistanceformingone terminal of the coil, said slip ring being arranged toembrace the most of the transformer flux, a brush for said slip ring,and means for adjustin the resistance of the circuit of said coil 1naccordance with the relative positions of said brush and slip ring.

4. A transformer having a coil in the formajl cfa helix,ajshort-circuited. turn of high re'' sistance forming one terminal ofthe coil, said short-circuited turn bein arranged to inclose the most ofthe trans ormer flux, a brush for making electrical connection with saidshort-circuited turn, a second shortcircuited turn connected in circuitwith the coil, a brush therefore, and means for adjusting the relativeposition of said last mentioned brush and short-circuited turn toregulate the resistance in circuit with the coil to compensate forresistance changes due t0 the rotation of said first mentionedshortcircuited turn.

5. A transformerhaving a coil in inductive relation thereon, a slip ringof 4high resistance forming one terminal of the coil, said slip ringbeing arranged to embrace the most of the transformer flux, a brush forsaid slip ring, and means for compensating for resistance changes due tothe rotation` of said slip ring and responsive thereto.

6. A transformer having a coil, a slip ring of high resistance formingone terminal of the coil, said slip ring being arranged to embrace themost ofthe transformer flux, a brush for said slip ring, and l means forcompensating for resistance changes due to the rotation of said slipring, said means including a second slip ring of similar resistance, andmeans for including moe or less of the same in circuit with the co1 7. Atransformer having a rotating coil, a brush, la 'conducting ringengaging said brush and forming one terminal of the coil and arranged torotate therewith, said ring being arranged so that the most of thetransformer flux passes therethrough, a brush arranged to slide alongthe turns of said coil as it revolves to cut more or less of the turnsof the coil in circuit, a second conducting ring in circuit with thecoil, and means for rotating said second conducting ring simultaneouslywith the rotation of the first conduct-ing ring, so that the variationsin resistance in circuit with said coil may be compensated for.

8. A transformer 'having a rotating coil, a brush, a conducting ringengaging said brush and forming one terminal of the coil, and arrangedto rotate therewith, said ring being arranged to embrace most of thetransformer flux, a brush arranged to slide along the turns of the coilas it revolves to cut more or less of the turns of the coil in circuit,a second conducting ring in circuit with said coil, both of saidconducting rings being of high resistance as compared with 130 the turnsof said coil, and means for rotating said second conducting ringsimultaneously with the rotation of the first conducting ring so thatthe variations in resistance in ircuit with said coil may be compensated9. A transformer having a rotating coil, a brush,- a conducting ringengaging said brush and forming one terminal o the coil, and arranged torotate therewith, said ring being arranged to embrace most of thetransformer flux, a brush arranged to slide along the turns of the coilas it revolves to cut more or less of the turns of the coil in circuit,a second conducting ring in circuit with said coil, both of Vsaidconducting rings being of high resistance as compared with the turnsofsaid coil, and means for rotating said second conduct-ing aingsimultaneously with the rotation of the rst conducting 1 ring so thatthe variations in resistance in circuit with said coil may becompensated for, and both of said rings being short circuited.

10. A transformer having a short circuited turn of high resistance, forforming one terminal thereof, said turn being arranged to embrace mostof the transformer flux, a brush engaging said terminal and movablerelatively thereto, and means for compensating for variations in theresistance of the circuit, due to the movement of the brush with respectto said turn.

In testimony Whereof,l have signed my name to this specification, in thepresence of two subscribing Witnesses.

. ALBERT S. HUBBARD. litnesses z GORHAM CROSBY, EDWIN SEGER.

